diff --git a/src/routers/deep_agent_chat.py b/src/routers/deep_agent_chat.py
index a055cec..0b8f497 100644
--- a/src/routers/deep_agent_chat.py
+++ b/src/routers/deep_agent_chat.py
@@ -177,7 +177,8 @@ async def chat_stream(request: DeepAgentChatRequest):
             if current_image_path:
                 bucket, object_name = current_image_path.split('/', 1)
                 image_url = get_presigned_url(oss_client=minio_client, bucket=bucket, object_name=object_name)
-                content.append({"type": "image_url", "image_url": {"url": image_url}})
+                if image_url is not None:
+                    content.append({"type": "image_url", "image_url": {"url": image_url}})
 
         final_messages = {
             "messages": [
diff --git a/src/server/utils/new_oss_client.py b/src/server/utils/new_oss_client.py
index b9e1180..b516b1c 100644
--- a/src/server/utils/new_oss_client.py
+++ b/src/server/utils/new_oss_client.py
@@ -80,7 +80,7 @@ def get_presigned_url(oss_client, bucket, object_name):
         return presigned_url
     except Exception as e:
         print(f"get_presigned_url exception :{e}")
-        return "object not found"
+        return None
 
 
 def is_minio_file_exist(oss_client: Minio, bucket_name: str, object_name: str) -> bool:
@@ -120,4 +120,4 @@ if __name__ == '__main__':
     img.show()
     img.save("result.png")
     # get_presigned_url(oss_client=minio_client, bucket="fida-test", object_name="furniture/sketches/07bf4cfe-4502-4821-b78f-7727bf409498.png")
-#
\ No newline at end of file
+#